Age of Extinction holds a dismal 18% on Rotten Tomatoes and 5.6 on IMDB and whilst there are better blockbusters out there these scores are a bit harsh. Most criticisms focus on the subplot between Shane and Tessa (i.e. the Romeo and Juliet law scene), the catering to the Chinese market, and the product placement. These weren't unwarranted but there were some improvements, like reducing the number of Autobots down to five and giving them some characteristics. I would be lying if a scene where Optimus Prime fights a robot dinosaur appeals to my inner 10-year-old. I personally think the bulk of the plot where Transformers are getting hunted and an company experiments on them would have fitted better as the first sequel.